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<H1 class="no-header">form_driver 3x</H1>
<PRE>
<STRONG><A HREF="form_driver.3x.html">form_driver(3x)</A></STRONG>                                         <STRONG><A HREF="form_driver.3x.html">form_driver(3x)</A></STRONG>




</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
       <STRONG>form_driver</STRONG>,  <STRONG>form_driver_w</STRONG>  -  command-processing loop of
       the form system


</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
       <STRONG>#include</STRONG> <STRONG>&lt;form.h&gt;</STRONG>
       <STRONG>int</STRONG> <STRONG>form_driver(FORM</STRONG> <STRONG>*</STRONG><EM>form</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>c</EM><STRONG>);</STRONG>
       <STRONG>int</STRONG> <STRONG>form_driver_w(FORM</STRONG> <STRONG>*</STRONG><EM>form</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>c</EM><STRONG>,</STRONG> <STRONG>wchar_t</STRONG> <EM>wch</EM><STRONG>);</STRONG>


</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>

</PRE><H3><a name="h3-form_driver">form_driver</a></H3><PRE>
       Once a form has been posted (displayed), you should funnel
       input  events to it through <STRONG>form_driver</STRONG>.  This routine has
       three major input cases:

       <STRONG>o</STRONG>   The input is a form  navigation  request.   Navigation
           request codes are constants defined in <STRONG>&lt;form.h&gt;</STRONG>, which
           are  distinct  from  the  key-  and  character   codes
           returned by <STRONG><A HREF="curs_getch.3x.html">wgetch(3x)</A></STRONG>.

       <STRONG>o</STRONG>   The input is a printable character.  Printable charac-
           ters (which must  be  positive,  less  than  256)  are
           checked according to the program's locale settings.

       <STRONG>o</STRONG>   The input is the KEY_MOUSE special key associated with
           an mouse event.


</PRE><H3><a name="h3-form_driver_w">form_driver_w</a></H3><PRE>
       This extension simplifies the use  of  the  forms  library
       using  wide characters.  The input is either a key code (a
       request) or a wide character returned by <STRONG><A HREF="curs_get_wch.3x.html">get_wch(3x)</A></STRONG>.  The
       type  must  be  passed  as  well, to enable the library to
       determine whether the parameter is a wide character  or  a
       request.


</PRE><H3><a name="h3-Form-driver-requests">Form-driver requests</a></H3><PRE>
       The form driver requests are as follows:

       <EM>Name</EM>               <EM>Description</EM>
       -------------------------------------------------------------------------
       REQ_BEG_FIELD      Move to the beginning of the field.
       REQ_BEG_LINE       Move to the beginning of the line.
       REQ_CLR_EOF        Clear to end of field from cursor.
       REQ_CLR_EOL        Clear to end of line from cursor.
       REQ_CLR_FIELD      Clear the entire field.
       REQ_DEL_CHAR       Delete character at the cursor.
       REQ_DEL_LINE       Delete line at the cursor.
       REQ_DEL_PREV       Delete character before the cursor.
       REQ_DEL_WORD       Delete blank-delimited word at the cursor.
       REQ_DOWN_CHAR      Move down in the field.
       REQ_DOWN_FIELD     Move down to a field.
       REQ_END_FIELD      Move to the end of the field.
       REQ_END_LINE       Move to the end of the line.
       REQ_FIRST_FIELD    Move to the first field.
       REQ_FIRST_PAGE     Move to the first page.
       REQ_INS_CHAR       Insert a blank at the cursor.
       REQ_INS_LINE       Insert a blank line at the cursor.
       REQ_INS_MODE       Enter insert mode.
       REQ_LAST_FIELD     Move to the last field.
       REQ_LAST_PAGE      Move to the last field.
       REQ_LEFT_CHAR      Move left in the field.

       REQ_LEFT_FIELD     Move left to a field.
       REQ_NEW_LINE       Insert or overlay a new line.
       REQ_NEXT_CHAR      Move to the next char.
       REQ_NEXT_CHOICE    Display next field choice.
       REQ_NEXT_FIELD     Move to the next field.
       REQ_NEXT_LINE      Move to the next line.
       REQ_NEXT_PAGE      Move to the next page.
       REQ_NEXT_PAGE      Move to the next page.
       REQ_NEXT_WORD      Move to the next word.
       REQ_OVL_MODE       Enter overlay mode.
       REQ_PREV_CHAR      Move to the previous char.
       REQ_PREV_CHOICE    Display previous field choice.
       REQ_PREV_FIELD     Move to the previous field.
       REQ_PREV_LINE      Move to the previous line.
       REQ_PREV_PAGE      Move to the previous page.
       REQ_PREV_WORD      Move to the previous word.
       REQ_RIGHT_CHAR     Move right in the field.
       REQ_RIGHT_FIELD    Move right to a field.
       REQ_SCR_BCHAR      Scroll the field backward a character.
       REQ_SCR_BHPAGE     Scroll the field backward half a page.
       REQ_SCR_BLINE      Scroll the field backward a line.
       REQ_SCR_BPAGE      Scroll the field backward a page.
       REQ_SCR_FCHAR      Scroll the field forward a character.
       REQ_SCR_FHPAGE     Scroll the field forward half a page.
       REQ_SCR_FLINE      Scroll the field forward a line.
       REQ_SCR_FPAGE      Scroll the field forward a page.
       REQ_SCR_HBHALF     Horizontal scroll the field backward half a line.
       REQ_SCR_HBLINE     Horizontal scroll the field backward a line.
       REQ_SCR_HFHALF     Horizontal scroll the field forward half a line.
       REQ_SCR_HFLINE     Horizontal scroll the field forward a line.
       REQ_SFIRST_FIELD   Move to the sorted first field.
       REQ_SLAST_FIELD    Move to the sorted last field.
       REQ_SNEXT_FIELD    Move to the sorted next field.
       REQ_SPREV_FIELD    Move to the sorted previous field.
       REQ_UP_CHAR        Move up in the field.
       REQ_UP_FIELD       Move up to a field.
       REQ_VALIDATION     Validate field.

       If  the  second  argument  is  a  printable character, the
       driver places it in the current position  in  the  current
       field.   If  it is one of the forms requests listed above,
       that request is executed.


</PRE><H3><a name="h3-Field-validation">Field validation</a></H3><PRE>
       The form library makes updates to  the  window  associated
       with  form  fields  rather than directly to the field buf-
       fers.

       The form driver provides low-level control over updates to
       the  form fields.  The form driver also provides for vali-
       dating modified fields to ensure that  the  contents  meet
       whatever  constraints  an  application  may  attach  using
       <STRONG>set_field_type</STRONG>.

       You can validate a field without making any changes to  it
       using  <STRONG>REQ_VALIDATION</STRONG>.   The  form driver also validates a
       field in these cases:

       <STRONG>o</STRONG>   a call to <STRONG>set_current_field</STRONG> attempts to move to a dif-
           ferent field.

       <STRONG>o</STRONG>   a  call to <STRONG>set_current_page</STRONG> attempts to move to a dif-
           ferent page of the form.

       <STRONG>o</STRONG>   a request attempts to move to a different field.

       <STRONG>o</STRONG>   a request attempts to move to a different page of  the
           form.

       In each case, the move fails if the field is invalid.

       If the modified field is valid, the form driver copies the
       modified data from the window associated with the field to
       the field buffer.


</PRE><H3><a name="h3-Mouse-handling">Mouse handling</a></H3><PRE>
       If  the  second argument is the KEY_MOUSE special key, the
       associated mouse event is translated into one of the above
       pre-defined  requests.   Currently only clicks in the user
       window (e.g., inside the form display area or the  decora-
       tion window) are handled.

       If you click above the display region of the form:

          a REQ_PREV_FIELD is generated for a single click,

          a REQ_PREV_PAGE is generated for a double-click and

          a REQ_FIRST_FIELD is generated for a triple-click.

       If you click below the display region of the form:

          a REQ_NEXT_FIELD is generated for a single click,

          a REQ_NEXT_PAGE is generated for a double-click and

          a REQ_LAST_FIELD is generated for a triple-click.

       If  you  click  at an field inside the display area of the
       form:

          <STRONG>o</STRONG>   the form cursor is positioned to that field.

          <STRONG>o</STRONG>   If you double-click a field,  the  form  cursor  is
              positioned  to  that field and <STRONG>E_UNKNOWN_COMMAND</STRONG> is
              returned.  This return value makes sense, because a
              double  click  usually means that an field-specific
              action should be returned.  It is exactly the  pur-
              pose  of this return value to signal that an appli-
              cation specific command should be executed.

          <STRONG>o</STRONG>   If  a  translation  into  a   request   was   done,
              <STRONG>form_driver</STRONG> returns the result of this request.

       If  you clicked outside the user window or the mouse event
       could  not  be  translated  into   a   form   request   an
       <STRONG>E_REQUEST_DENIED</STRONG> is returned.


</PRE><H3><a name="h3-Application-defined-commands">Application-defined commands</a></H3><PRE>
       If the second argument is neither printable nor one of the
       above pre-defined form requests, the driver assumes it  is
       an application-specific command and returns <STRONG>E_UNKNOWN_COM-</STRONG>
       <STRONG>MAND</STRONG>.  Application-defined commands should be defined rel-
       ative  to  <STRONG>MAX_COMMAND</STRONG>,  the  maximum  value of these pre-
       defined requests.


</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
       <STRONG>form_driver</STRONG> returns one of the following error codes:

       <STRONG>E_OK</STRONG> The routine succeeded.

       <STRONG>E_BAD_ARGUMENT</STRONG>
            Routine detected an incorrect or  out-of-range  argu-
            ment.

       <STRONG>E_BAD_STATE</STRONG>
            Routine was called from an initialization or termina-
            tion function.

       <STRONG>E_NOT_POSTED</STRONG>
            The form has not been posted.

       <STRONG>E_INVALID_FIELD</STRONG>
            Contents of field is invalid.

       <STRONG>E_REQUEST_DENIED</STRONG>
            The form driver could not process the request.

       <STRONG>E_SYSTEM_ERROR</STRONG>
            System error occurred (see <STRONG>errno</STRONG>).

       <STRONG>E_UNKNOWN_COMMAND</STRONG>
            The form driver code saw an unknown request code.


</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
       <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>,        <STRONG><A HREF="form.3x.html">form(3x)</A></STRONG>,        <STRONG><A HREF="form_field_buffer.3x.html">form_field_buffer(3x)</A></STRONG>,
       <STRONG><A HREF="form_field_validation.3x.html">form_field_validation(3x)</A></STRONG>,  <STRONG><A HREF="form_fieldtype.3x.html">form_fieldtype(3x)</A></STRONG>, <STRONG>form_vari-</STRONG>
       <STRONG><A HREF="form_variables.3x.html">ables(3x)</A></STRONG>, <STRONG><A HREF="curs_getch.3x.html">getch(3x)</A></STRONG>.


</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
       The header file <STRONG>&lt;form.h&gt;</STRONG> automatically includes the header
       files <STRONG>&lt;curses.h&gt;</STRONG>.


</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
       These  routines  emulate the System V forms library.  They
       were not supported on Version 7 or BSD versions.


</PRE><H2><a name="h2-AUTHORS">AUTHORS</a></H2><PRE>
       Juergen Pfeifer.  Manual  pages  and  adaptation  for  new
       curses by Eric S. Raymond.



                                                        <STRONG><A HREF="form_driver.3x.html">form_driver(3x)</A></STRONG>
</PRE>
<div class="nav">
<ul>
<li><a href="#h2-NAME">NAME</a></li>
<li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
<li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
<ul>
<li><a href="#h3-form_driver">form_driver</a></li>
<li><a href="#h3-form_driver_w">form_driver_w</a></li>
<li><a href="#h3-Form-driver-requests">Form-driver requests</a></li>
<li><a href="#h3-Field-validation">Field validation</a></li>
<li><a href="#h3-Mouse-handling">Mouse handling</a></li>
<li><a href="#h3-Application-defined-commands">Application-defined commands</a></li>
</ul>
</li>
<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
<li><a href="#h2-NOTES">NOTES</a></li>
<li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
<li><a href="#h2-AUTHORS">AUTHORS</a></li>
</ul>
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